A feral cat

The examples and perspective in this article deal primarily with Australia and New Zealand and do not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (April 2012)

A feral cat is a descendant of a domesticated cat that has returned to the wild. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats are born in the wild; the offspring of a stray cat can be considered feral if born in the wild.^[1]

In many parts of the world, feral cats are descendants of domestic cats that were left behind by travelers. Because cats are not native to all parts of the world, feral cats can cause harm to local environments by preying on local species.^{[citation needed]} This is especially true on islands where feral cats have sometimes had a substantial and deleterious effect on the local fauna.^{[citation needed]}

Behavior of "feral" cats[link]

Feral versus stray[link]

A feral cat showing defensive behavior

The term "feral" is sometimes used to refer to an animal that does not appear friendly when approached by humans, but the term can apply to any domesticated animal without human contact.^[1] Hissing and growling are self-defense behaviors, which, over time, may change as the animal (whether "feral" or "stray") begins to trust humans that provide food, water, and care.^[2][3]

Feral cats that are born and living outdoors, without any human contact or care, have been shown to be adoptable and can be tamed by humans, provided they are removed from a wild environment before truly feral behaviors are established.^[2][4]

Life span and survival[link]

The lifespan of feral cats is hard to determine accurately, although one study reported a median age of 4.7 years, with a range between 0 to 8.3 years,^[5] while another paper referenced a mean life span of 2 – 8 years.^[6] For contrast, in captivity, an average life expectancy for male indoor cats at birth is 12 to 14 years,^[7] with females usually living a year or two longer.

History[link]

During the Age of Discovery, ships released rabbits onto islands to provide a future food source for other travelers. They eventually multiplied out of control and cats were introduced to keep their numbers, and that of mice and rats, down. The cats tended to favor local species as they were ecologically naive and easier to hunt. Their numbers too increased dramatically and soon they colonised many areas and were seen as pests too.

Historical records date the arrival of feral cats in Australia at around 1824.^[8] Despite that, it has been suggested that feral cats have been present in Australia since before European settlement, and may have arrived with Dutch shipwrecks in the 17th century, or even before that, arriving from present-day Indonesia with Macassan fisherman and trepangers who frequented Australia's shores.^[9]

Diet and predators[link]

This unreferenced section requires citations to ensure verifiability.

Feral cats in Australia prey on a variety of wildlife. In arid and semi-arid environments, they eat mostly introduced European rabbits and house mice; in forests and urbanised areas, they eat mostly native marsupial prey (based on 22 studies summarised in Dickman 1996). In arid environments where rabbits do not occur, native rodents are taken. Birds and reptiles form a smaller part of the diet.

Feral cats may be apex predators in some local ecosystems. In others, they may be preyed on by feral dogs, dingoes, coyotes, wolves, bears, cougars, leopards, bobcats, lynx, hyenas, fishers, crocodilians, snakes, foxes and birds of prey.

Effects on wildlife[link]

Feral cats can be effective hunters of small animals

The impact of domestic cats on wildlife is a century old debate. In a 1916 report for the Massachusetts State Board of Agriculture titled The Domestic Cat: Bird Killer, Mouser and Destroyer of Wildlife, noted ornithologist Edward Howe Forbush stated in the preface:

Questions regarding the value or inutility of the domestic cat, and problems connected with limiting its more or less unwelcome outdoor activities, are causing much dissension. The discussion has reached an acute stage. Medical men, game protectors and bird lovers call on legislators to enact restrictive laws. Then ardent cat lovers rouse themselves for combat. In the excitement of partisanship many loose and ill-considered statements are made.^[10]

The report cited Extinct Birds, published in 1905 by zoologist Walter Rothschild, who stated, "man and his satellites, cats, rats, dogs, and pigs are the worst and in fact the only important agents of destruction of the native avifaunas wherever they go."^[11] Rothschild gave several examples of cats causing the extermination of some bird species on islands.

Some farmers and gamekeepers see feral cats as vermin. Feral cats catch and eat ground nesting birds such as pheasants and partridge. To protect their birds, some gamekeepers set traps and shoot feral cats as part of pest control.^{[citation needed]}.

Australia[link]

Feral cat killing a native Australian cockatoo

Feral cats in Australia have caused the decline and extinction of animals on islands as they have been shown to cause a significant impact on ground birds and small native mammals.^[9] Feral cats have also stopped any attempts to re-introduce threatened species back into areas where they have become extinct as the cats have simply hunted and killed the newly released animals.^[12] Numerous Australian environmentalists claim the feral cat has been an ecological disaster in Australia, inhabiting most ecosystems except dense rainforest, and being implicated in the extinction of several marsupial and placental mammal species.^[13] Although a researcher disagrees with this view (Abbot 2002). Some others believe that there is little sound evidence that feral cats significantly affect native wildlife throughout the mainland and that it is only on the islands that they are a threat (Jones 1989; Wilson et al. 1992).^[9] Difficulties in separating the effects of cats from that of foxes (also introduced) and environmental effects have hindered research into this. Cats have co-existed with all mammal species in Tasmania for nearly 200 years.^[8] The Western Shield program in Western Australia, involving broad-scale poisoning of foxes, has resulted in rapid recoveries of many species of native mammals in spite of the presence of feral cats throughout the baited area.^[8] In 2005, however, a study was published which for the first time found proof of feral cats causing declines in native mammals.^[14] An experiment conducted in Heirisson Prong (Western Australia) compared small mammal populations in areas cleared of both foxes and cats, of foxes only, and a control plot. Researchers found mammal populations were lower in areas cleared of foxes only and in the control plots.

Cats may also play a further role in Australia's human altered ecosystems; with foxes they may be controlling introduced rabbits, particularly in arid areas, which themselves cause ecological damage.^[13] Cats are believed to have been a factor in the extinction of the only mainland bird species to be lost since European settlement, the Paradise Parrot.

Australian folklore holds that some feral cats in Australia have grown so large as to cause inexperienced observers to claim sightings of other species such as puma etc. This folklore is being shown to be more fact than fiction, with the recent shooting of an enormous feline,^[15] in the Gippsland area of Victoria. Subsequent DNA test showed the feline to be Felis silvestris catus.^[16] Subsequent news of large feral cat sightings appear almost monthly in Australia, and the evidence is very good to suggest a breeding population of these enormous felines in the south-eastern states Victoria and New South Wales.^[17]

New Zealand[link]

The fauna of New Zealand has evolved in isolation for millions of years without the presence of mammals (apart from a few bat species). Consequently, birds dominated the niches occupied by mammals and many became flightless. The introduction of mammals after settlement by Māori from about the 12th century had a huge effect on the indigenous biodiversity. European explorers and settlers brought cats on their ships and the presence of feral cats were recorded from the latter decades of the 19th century.^[18] It is estimated that feral cats have been responsible for the extinction of six endemic bird species and over 70 localised subspecies as well as depleting bird and lizard species.^[19]

Islands[link]

Consequences of introduction[link]

The Stephens Island Wren became extinct within two years of the introduction of cats to Stephens Island

Many islands host ecologically naive animal species; that is, animals that do not have predator responses for dealing with predators such as cats.^[20] Feral cats introduced to such islands have had a devastating impact on these islands' biodiversity. They have been implicated in the extinction of several species and local extinctions, such as the hutias from the Caribbean, the Guadalupe Storm Petrel from Pacific Mexico, the Stephens Island wren; in a statistical study, they were a significant cause for the extinction of 40% of the species studied.^[21] Moors and Atkinson wrote, in 1984, "No other alien predator has had such a universally damaging effect."^[20]

Feral cats, along with rabbits, some sea birds, and sheep, form the entire large animal population of the remote Kerguelen Islands in the southern Indian Ocean.

Restoration[link]

Because of the damage cats cause in islands and some ecosystems, many conservationists working in the field of island restoration have worked to remove feral cats. (Island restoration involves the removal of introduced species and reintroducing native species). As of 2004, 48 islands have had their feral cat populations removed, including New Zealand's network of offshore island bird reserves,^[22] and Australia's Macquarie Island. Larger projects have also been undertaken, including their complete removal from Ascension Island. The cats, introduced in the 19th century, caused a collapse in populations of nesting seabirds. The project to remove them from the island began in 2002, and the island was cleared of cats by 2004. Since then, seven species of seabird that had not nested on the island for 100 years have returned.^[23]

In some cases, the removal of cats had unintended consequences. An example is Macquarie Island (off the coast of Tasmania), where the removal of cats caused an explosion in the number of rabbits, rats, and mice that harm native seabirds.^[24][25][26] The removal of the rats and rabbits was scheduled for 2007 and it could take up to seven years and cost $24 million.^[27]

Hybridisation with wild felids[link]

Feral cats have interbred with wildcats to various extents throughout the world, the first reported case occurring more than 200 years ago. The significance of hybridisation is disputed and hinges on whether the domestic cat is classified as conspecific with the wildcat or a separate species.^[28] (see Genetic pollution) In some locations, high levels of hybridisation has led to difficulties in distinguishing a "true" wildcat from feral domestic and domestic hybrid cats, which can complicate conservation efforts.^[29] Some researchers argue that "pure" wildcats do not exist anymore, but this is disputed by others.^[28] One study in Scotland suggests that while "true" Scottish wildcats are unlikely to exist, the current wildcat population is distinct enough from domestic cats to be worth protecting.^[30]

Zoonotic risk[link]

There is concern about the role of feral cat colonies, wild dogs, and other native mammals, as a vector of diseases, particularly toxoplasmosis, giardiasis (esp. from beavers), rabies (e.g. raccoons), Campylobacter, Parvovirus and other diseases and parasites that can infect both humans and animals. Felids such as cougars and cats, the mammals they feed on, and undercooked meat and chicken are a source of Toxoplasma gondii, which causes toxoplasmosis.^[31]

Colonies[link]

Population[link]

Feral cat

A feral cat colony (or "clowder") is a population of feral cats. The term is used primarily when a noticeable population of feral cats live together in a specific location and use a common food source. The term is not typically applied to solitary cats passing through an area. A clowder can range from 3-25 cats.^[5] Their locations vary, some hiding in alleyways or in large parks.

Members consist of adult females, their young, and some adult males. Unneutered males in a clowder fight each other for territory and for females. Some will be driven out to find another place to live.

Feral cats who have been trapped in many warm areas where fleas exist are usually found to have a large number of fleas, causing them to be anemic. Both the fleas, and the food source, if limited to garbage and rodents, cause the cats to have intestinal microorganisms (such as coccidia or giardia) and other parasites (commonly known as roundworms, tapeworms, and hookworms), which lead to diarrhea and subsequent dehydration. They also can have ear mites, ringworm, and upper respiratory infections. Others are wounded in mating-fights and die from the infected wounds. Still others eventually contract feline immunodeficiency virus or feline leukemia due to the constant transmission of blood and bodily fluids via fighting and sexual activity.

While all of these illnesses are quite treatable, there must be humans to intervene to stop these illnesses from becoming fatal. Due to the number of health problems to which they are subjected, and their fragile immune systems, kittens in the clowders usually do not survive^{[citation needed]}.

Control and management[link]

This section may require cleanup to meet Wikipedia's quality standards. No cleanup reason has been specified. Please help improve this section if you can; the talk page may contain suggestions. (November 2010)

A clowder of feral cats

In Trap-Neuter-Return (TNR), volunteers trap feral cats, sterilize them through spaying or neutering, and then release them, though some keep kittens or cats which are more tame. Variations of the program include testing and inoculation against rabies and other viruses and sometimes long-lasting flea treatments.^[32] TNR programs are only now being introduced in some urban and suburban areas, such as Adelaide. More recently, such programs have been introduced in Sydney by the "World League for Protection of Animals". While various long-term studies have shown TNR is effective in stopping the breeding of cats in the wild and reducing the population over time,^[33][34][35] opponents of TNR frequently cite a study by Castillo (2003)^[36] as evidence TNR does not work.^[37] Many humane societies and animal rescue groups of varying sizes throughout the United States have some type of TNR program.^[38][39][40] The practice is endorsed by the Humane Society of the United States and the National Animal Control Association.^[41][42] While the United States Department of Defense does not formally advocate TNR, it does provide information to military installations on how to implement TNR programs.^[43] The main message from the department is that population control programs must be humane.^[44]

On islands, on which the vacuum effect does not apply^{[citation needed]}, eradication methods include hunting, trapping, poison baiting and biological controls. For example on Marion Island cats were infected with the feline panleukopenia virus, which drastically reduced their population within six years.^[45] The remaining cats were killed by shooting.^{[citation needed]}

Feral cats can also be controlled by larger native predators like coyotes, dingoes, or foxes because many cats are too small to defend themselves against larger predators.^{[citation needed]}

The multiple, managed, feral colonies at the Colosseum in Rome exceed 250 cats. Other notable colonies include the Canadian Parliamentary Cats, and the cats of Jerusalem ^[46]

See also[link]

• The Society for the Improvement of Conditions for Stray Animals (SICSA)

References[link]

External links[link]

Wikimedia Commons has media related to: Feral cats

• A feral cat advocacy organization's explanation of feral cats Stray Cat Alliance
• Feral cat control in the UK
• The cat debate American Veterinary Medical Association
• Feral cats are everybody's problem Southern Oregon Mail Tribune
• Study of the feral cats in Portsmouth Naval Dockyard, UK with photos and scientific papers
• Feral cat guides at Alley Cat Allies
• List of Feral Cat Rescue Groups By State Humane Society of the United States
• List of Humane Societies and Rescue Groups With TNR Programs Alley Cat Rescue

A feral horse (an American Mustang) in Wyoming, USA

Soay sheep in St Kilda, Scotland

A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer.

As with any introduced species, the introduction of feral animals or plants to non-native regions may disrupt ecosystems and has, in some cases, contributed to extinction of indigenous species. Feral species may however eliminate "problem" species such as rodents, harmful insects, or aggressive plants. Likewise returning lost species to their environment can have beneficial effects, such as bringing damaged ecosystems back into balance.

Definitions[link]

The word feral used to describe domesticated species returning to the wild derives from Latin fera, "a wild beast".

Animals[link]

Stray kitten in Nablus

One of the numerous dictionary definitions of a feral animal states that a feral animal is an animal which has escaped from a domestic or captive status and is living more or less as a wild animal. Other definitions realize the shortcomings of the first definition and simply say that a feral animal is an animal which has changed from being domesticated to being wild, natural, or untamed.

Zoologists generally exclude from the ‘feral’ category animals which were genuinely wild before they escaped from captivity: neither lions escaped from a zoo nor the sea eagles (Haliaeetus albicilla) recently re-introduced into the UK are regarded as 'feral'. As far as animals are concerned, this article assumes the ‘zoological definition’ of feral. Some common examples of animals with feral populations are horses, dogs, goats, cats, and pigs.

The term 'feral' should not be used to describe the naturalization of a wild (i.e. non-domesticated) species.^[1] Nor should "feral" be used to describe a population of a species which although descended from a domesticated population has severed itself from dependence on humans and lived independently in the wild for a long period.^[2]

Plants[link]

Domesticated plants that revert to wild are usually referred to as escaped, introduced or naturalized rather than feral. However, the adaptive and ecological variables seen in plants that go wild closely resemble those of animals.

Variables[link]

Susceptibility[link]

Certain familiar animals go feral easily and successfully, while others are much less inclined to wander and usually fail promptly outside domestication.

Degree[link]

Some species will detach readily from humans and pursue their own devices, but do not stray far or spread readily. Others depart and are gone, seeking out new territory or range to exploit and displaying active invasiveness.

Persistence[link]

Whether they leave readily and venture far, the ultimate criterion for success is longevity. Persistence depends on their ability to establish themselves and reproduce reliably in the new environment.

Tenure of domestication[link]

Neither the duration nor the intensity with which a species has been domesticated offers a useful correlation with its feral potential.

Examples of feral animals[link]

Feral dogs in Bucharest

The cat returns readily to a feral state if it has not been socialized properly in its young life. (See Feral cats.) These cats, especially if left to proliferate, are frequently considered to be pests in both rural and urban areas, and may be blamed for devastating the bird, reptile and mammal populations. A local population of feral cats living in an urban area and using a common food source is sometimes called a feral cat colony. As feral cats multiply quickly, it is difficult to control their populations. Animal shelters attempt to adopt out feral cats, especially kittens, but often are overwhelmed with sheer numbers and euthanasia is used. In rural areas, excessive numbers of feral cats are often shot. More recently, the "Trap-Neuter-Return" method has been used in many locations as an alternate means of managing the feral cat population.

The goat is one of the oldest domesticated creatures, yet readily goes feral and does quite well on its own.

The dromedary camel, which has been domesticated for well over 3,000 years, will also readily go feral. A substantial population of feral dromedaries, descended from pack animals that escaped in the 19th and early 20th centuries, thrives in the Australian interior today.

Sheep are close contemporaries and cohorts of goats in the history of domestication, but the domestic sheep is quite vulnerable to predation and injury, and thus rarely if ever is seen in a feral state. However, in places where there are few predators, they get on well, for example in the case of the Soay sheep.

Water buffalo run rampant in Western and Northern Australia. This is the only part of the world where they are legally hunted in their original range. The Australian government encourages the hunting of feral water buffalo because of their large numbers.

Cattle have been domesticated since the neolithic era, but can do well enough on open range for months or even years with little or no supervision. Their ancestors, the Aurochs, were quite fierce, on par with the modern Cape Buffalo. Modern cattle, especially those raised on open range, are generally more docile, but when threatened can display aggression. Cattle, particularly those raised for beef, are often allowed to roam quite freely and have established long term independence in Australia, New Zealand and several Pacific Islands along with small populations of semi-feral animals roaming the southwestern United States and northern Mexico. Such cattle are variously called Mavericks, Scrubbers or Cleanskins. Most free roaming cattle, however untamed, are generally too valuable not to be eventually rounded up and recovered in closely settled regions.

Horses and donkeys, domesticated about 5000 BCE, are feral in open grasslands worldwide (see feral horse). In Portugal, feral horses are called Sorraia; in Australia, they are called Brumbies; in the American west, they are called Mustangs. Other isolated feral populations exist, including the Chincoteague Pony and the Banker Horse. They are often referred to as "wild horses," but this is a misnomer. There are truly "wild" horses that have never been tamed, most notably Przewalski's Horse. While the horse was originally indigenous to North America, the wild ancestor died out at the end of the last Ice Age. In both Australia and the Americas, modern "wild" horses descended from domesticated horses brought by European explorers and settlers that escaped, spread, and thrived.

Feral donkeys or burros in Nevada

The pig (hog) has established feral populations worldwide, most notably in Australia, New Zealand, the United States, New Guinea and the Pacific Islands. Pigs were introduced to the Melanesian and Polynesian regions by humans from several thousand to five hundred years ago, and to the Americas within the past 500 years. In Australia, domesticated pigs escaped in the 18th century, and now cover 40 percent of Australia^[3] with a population estimated at 30 million. While pigs were doubtlessly brought to New Zealand by the original Polynesian settlers, this population had become extinct by the time of European colonization, and all feral pigs in New Zealand today are descendants of European stock. Many European wild boar populations are also partially descended from escaped domestic pigs and are thus technically feral animals within the native range of the ancestral species.

Rock Pigeons were formerly kept for their meat or more commonly as racing animals and have established feral populations in cities worldwide.

Colonies of honey bees often escape into the wild from managed apiaries when they swarm; their behavior, however, is no different from their behavior "in captivity", until and unless they breed with other feral honey bees of a different genetic stock, which may lead them to become more docile or more aggressive (see Africanized bees).

Large colonies of feral parrots are present in various parts of the world, with Rose-ringed Parakeets, Monk Parakeets and Red-masked Parakeets (the latter of which became the subject of the documentary film, The Wild Parrots of Telegraph Hill) being particularly successful outside of their native habitats and adapting well to suburban environments.

Harmful and beneficial effects of feralization[link]

This unreferenced section requires citations to ensure verifiability.

Rock doves, also known as pigeons: feral animals who nonetheless live in close proximity to humans

A Feral Barbary Dove in Tasmania, Australia. Also known as a Ringneck Dove or Ring Dove (Streptopelia risoria)

Ecological impact[link]

A feral population can have a significant impact on an ecosystem by predation on vulnerable plants or animals, or by competition with indigenous species. Feral plants and animals constitute a significant share of invasive species, and can be a threat to endangered species.

Genetic pollution[link]

Animals of domestic origin sometimes can produce fertile hybrids with native, wild animals which leads to genetic pollution (not a clear term itself) in the naturally evolved wild gene pools, many times threatening rare species with extinction. Cases include the mallard duck, wild boar, the rock dove or pigeon, the Red Junglefowl (Gallus gallus) (ancestor of all chickens), carp, and more recently salmon^{[citation needed]}. Other examples of genetic swamping lie in the breeding history of dingoes. Dingoes are a wild true dogs that will interbreed with dogs of other origins, thus leading to the proliferation of dingo hybrids and the possibility of the extinction of pure wild dingoes.^[4] Researches in Scotland have remarked on a similar pheonomenon of the genetic mixing of feral domestic cats and their wild counterparts.^[5] In some cases like rabbits, genetic pollution seems not to be noticed. There is much debate over the degree to which feral hybridization compromises the purity of a wild species. In the case of the mallard, for example, some claim there are no populations that are completely free of any domestic ancestor.^{[citation needed]}

Zoonotic potential[link]

This section requires expansion.

Feral animals may become reservoirs of diseases and transmit them to humans. The spread of rabies from feral dogs and cats is a very grave threat. There is a need to have effective control measures especially of feral dog and cat populations.

Economic harm[link]

Feral animals compete with domestic livestock, and may degrade fences, water sources, and vegetation (by overgrazing or introducing seeds of invasive plants). Though hotly disputed, some cite as an example the competition between feral horses and cattle in the western United States. Another example is of goats competing with cattle in Australia, or goats that degrade trees and vegetation in environmentally-stressed regions of Africa. Accidental crossbreeding by feral animals may result in harm to breeding programs of pedigreed animals; their presence may also excite domestic animals and push them to escape. Feral populations can also pass on transmissible infections to domestic herds. Loss to farmers by aggressive feral dog population is common in India.

Economic benefits[link]

Many feral animals can sometimes be captured at little cost and thus constitute a significant resource. Throughout most of Polynesia and Melanesia feral pigs constitute the primary sources of animal protein. Prior to the Wild and Free-Roaming Horses and Burros Act of 1971, American Mustangs were routinely captured and sold for horsemeat. In Australia feral goats, pigs and dromedaries are harvested for the export for their meat trade. At certain times, animals were sometimes deliberately left to go feral, typically on islands^{[citation needed]}, in order to be later recovered for profit or food use for travelers (particularly sailors) at the end of a few years.

Scientific value[link]

Populations of feral animals present good sources for studies of population dynamics, and especially of ecology and behavior (ethology) in a wild state of species known mainly in a domestic state. Such observations can provide useful information for the stock breeders or other owners of the domesticated conspecifics (i.e. animals of the same species).

Genetic diversity[link]

Feral populations sometimes preserve or develop characteristics which do not always exist in the fully domesticated equivalent. Therefore, they contribute to domestic biodiversity and often deserve to be preserved, be it in their feral environment or as domestic animals. For example, feral species that are usually subjects of eradication in Australia or New Zealand are currently the subject of study to determine if there is a need for their preservation.^{[citation needed]}

Cultural or historic value[link]

American Mustangs have been protected since 1971 in part due to their romance and connection to the history of the American West. A similar situation is that of the wild horses from the Letea Forest in the Danube Delta. Romanian government is considering the protection of the feral horses and transforming them into a touristic attraction, after it first approved the killing of the entire population. Due to the intervention of numerous organizations and widespread popular disapproval of the Romanians the horses have been saved, but still have an uncertain fate as their legal status is unclear and local people continue to claim the right to use the horses in their own interest.

See also[link]

• Abandoned pets
• Domestication
• Feral dog
• Estray
• Feral children
• Feral (subculture)
• Invasive species
• Overpopulation in companion animals
• Stray dogs in Bangkok

References[link]

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2007)

External links[link]

Look up feral in Wiktionary, the free dictionary.

Note: Links that treat feral animals as a mere pest issue are the norm.

• National Wild Horse and Burro Program
• Feral Camels, Information from Australian Department of Agriculture regarding Australia's estimated 300,000 feral camels.
• Alley Cat Allies, a feral cat advocacy organization

Domestic cat[1]
Conservation status
Domesticated
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Felidae
Genus:	Felis
Species:	F. catus
Binomial name
Felis catus[2] Linnaeus, 1758[3]
Synonyms
Felis silvestris catus (subjective synonym)[4] Felis catus domestica (invalid junior synonym)[5]

The domestic cat^[1][2] (Felis catus^[2] or Felis silvestris catus^[4], informally Felis domesticus^[6][7]) is a small, usually furry, domesticated, carnivorous mammal. It is often called the housecat when kept as an indoor pet,^[8] or simply the cat when there is no need to distinguish it from other felids and felines. Cats are valued by humans for companionship and ability to hunt vermin and household pests. They are primarily nocturnal.^[9]

Cats are similar in anatomy to the other felids, with strong, flexible bodies, quick reflexes, sharp retractable claws, and teeth adapted to killing small prey. As crepuscular predators, cats use their acute hearing and ability to see in near darkness to locate prey. Not only can cats hear sounds too faint for human ears, they can also hear sounds higher in frequency than humans can perceive. This is because the usual prey of cats (particularly rodents such as mice) make high frequency noises, so the hearing of the cat has evolved to pinpoint these faint high-pitched sounds. Cats also have a much better sense of smell than humans.

Despite being solitary hunters, cats are a social species, and cat communication includes the use of a variety of vocalizations (meowing, purring, trilling, hissing, growling and grunting) as well as pheromones and types of cat-specific body language.^[10]

Cats have a rapid breeding rate. Under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy. Failure to control the breeding of pet cats by spaying and neutering and the abandonment of former household pets has resulted in large numbers of feral cats worldwide, with a population of up to 60 million of these animals in the United States alone.^[11]

Since cats were cult animals in ancient Egypt, it was commonly believed to have been domesticated there,^[12] but there may have been instances of domestication as early as the Neolithic.^[13] A genetic study in 2007 revealed that all house cats are descended from as few as five female African Wildcats (Felis silvestris lybica) c. 8000 BCE, in the Middle East.^[12][14] Cats are currently the most popular pet in the world, now found almost everywhere in the world.^[15]

Nomenclature and etymology[link]

The English word cat (Old English catt) is in origin a loanword, introduced to many languages of Europe from Latin cattus and Byzantine Greek κάτια, including Portuguese and Spanish gato, French chat, German Katze, Lithuanian katė and Old Church Slavonic kotka, among others. The ultimate source of the word is Afro-Asiatic, presumably from Late Egyptian čaute, the feminine of čaus "African wildcat". The word was introduced (together with the domestic animal) to the Roman Republic by the 1st century BCE. An alternative word with cognates in many languages is English puss (pussycat). Attested only from the 16th century, it may have been introduced from Dutch poes or from Low German puuskatte, related to Swedish kattepus, or Norwegian pus, pusekatt. The etymology of this word is unknown, but it appears to reflect the native Germanic name of the animal.^[16]

While wildcats are the ancestral species from which domestic cats are descended, there are several intermediate stages between domestic pet and pedigree cats and these entirely wild cats. The semi-feral cat is a cat that is not owned by any one individual, but is generally friendly to people and may be fed by several households. Feral cats are associated with human habitations and may be fed by people or forage in rubbish, but are wary of human interaction.^[17]

A group of cats is referred to as a "clowder", a male cat is called a "tom" (or a "gib", if neutered), and a female is called a "molly" or "queen". The male progenitor of a cat, especially a pedigreed cat, is its "sire", and its female progenitor is its "dam". An immature cat is called a "kitten". In medieval Britain, the word kitten was interchangeable with the word catling.

A cat whose ancestry is formally registered is called a pedigreed cat, purebred cat, or a show cat. In strict terms, a pure-bred cat is one whose ancestry contains only individuals of the same breed. A pedigreed cat is one whose ancestry is recorded, but may have ancestors of different breeds. Cats of unrecorded mixed ancestry are referred to as domestic longhairs and domestic shorthairs or commonly as random-bred, moggies, mongrels, or mutt-cats.

Taxonomy and evolution[link]

The wildcat Felis silvestris is a close relative and possible ancestor of the domestic cat.

The Felids are a rapidly evolving family of mammals that share a common ancestor only 10–15 million years ago,^[18] and include, in addition to the domestic cat, lions, tigers, cougars, and many others. Within this family, domestic cats (Felis catus) are part of the genus Felis, which is a group of small cats containing seven species.^[1][19] Members of the genus are found worldwide and include the Jungle Cat (Felis chaus) of southeast Asia, the African Wildcat (Felis silvestris lybica), the Chinese Mountain Cat (Felis bieti) and the Arabian Sand Cat (Felis margarita).^[20]

All the cats in this genus share a common ancestor that probably lived around 6–7 million years ago in Asia.^[21] Although the exact relationships within the Felidae are still uncertain,^[22][23] both the Chinese Mountain Cat and the African Wildcat are close relatives of the domestic cat and are both classed as subspecies of the Wildcat Felis silvestris.^[4][22] As domestic cats are little altered from wildcats, they can readily interbreed. This hybridization may pose a danger to the genetic distinctiveness of wildcat populations, particularly in Scotland and Hungary.^[24]

The domestic cat was first classified as Felis catus by Carolus Linnaeus in the tenth edition of his Systema Naturae of 1758.^[1][3] However, because of modern phylogenetics, domestic cats are now usually regarded as another subspecies of the Wildcat Felis silvestris.^[1][4][25] This has resulted in mixed usage of the terms, as the domestic cat can be called by its subspecies name, Felis silvestris catus.^[1][4][25] Wildcats have also been referred to as various subspecies of F. catus,^[25] but in 2003 the International Commission on Zoological Nomenclature fixed the name for wildcats as F. silvestris.^[26] The most common name in use for the domestic cat remains F. catus, following a convention for domesticated animals of using the earliest (the senior) synonym proposed.^[26] Sometimes the domestic cat is called Felis domesticus^[27] or Felis domestica,^[1] the term coined by German naturalist Johann Christian Polycarp Erxleben in 1777. These are not valid taxonomic names, and Linnaeus's binomial takes precedence.^[28]

Cats have either a mutualistic or commensal relationship with humans. However, in comparison to dogs, cats have not undergone major changes during the domestication process, as the form and behavior of the domestic cat are not radically different from those of wildcats, and domestic cats are perfectly capable of surviving in the wild.^[29][30] This limited evolution during domestication means that domestic cats tend to interbreed freely with feral cats, which distinguishes them from other domesticated animals.^[17] However, several natural behaviors and characteristics of wildcats may have preadapted them for domestication as pets.^[30] These traits include their small size, social nature, obvious body language, love of play and relatively high intelligence;^[31]:12–17 they may also have an inborn tendency towards tameness.^[30]

There are two main theories about how cats were domesticated. In one, people deliberately tamed cats in a process of artificial selection, as they were useful predators of vermin.^[32] However, this has been criticized as implausible, because there may have been little reward for such an effort: cats generally do not carry out commands and, although they do eat rodents, other species such as ferrets or terriers may be better at controlling these pests.^[4] The alternative idea is that cats were simply tolerated by people and gradually diverged from their 'wild' relatives through natural selection, as they adapted to hunting the vermin found around humans in towns and villages.^[4]

Genetics[link]

Blue-eyed cats with white fur have a high incidence of genetic deafness.^[33]

The domesticated cat and its closest wild ancestor are both diploid organisms that possess 38 chromosomes^[34] and roughly 20,000 genes.^[35] About 250 heritable genetic disorders have been identified in cats, many similar to human inborn errors.^[36] The high level of similarity among the metabolisms of mammals allows many of these feline diseases to be diagnosed using genetic tests that were originally developed for use in humans, as well as the use of cats in the study of the human diseases.^[37][38]

An example of a mutation that is shared among all felines, including the big cats, is a mutant chemosensor in their taste buds that prevents them from tasting sweetness, which may explain their indifference to fruits, berries, and other sugary foods.^[39] In some breeds of cats congenital deafness is very common, with most white cats (but not albinos) being affected, particularly if they also have blue eyes.^[33] The genes responsible for this defect are unknown, but the disease is studied in the hope that it may shed light on the causes of hereditary deafness in humans.^[40]

Since a large variety of coat patterns exist within the various cat breeds, the cat is an excellent animal to study the coat genetics of hair growth and coloration.^[41] Several genes interact to produce cats' hair color and coat patterns. Different combinations of these genes give different phenotypes. For example, the enzyme tyrosinase is needed to produce the dark pigment melanin and Burmese cats have a mutant form that is only active at low temperatures, resulting in color appearing only on the cooler ears, tail and paws.^[42] A completely inactive gene for tyrosinase is found in albino cats, which therefore lack all pigment.^[43] Hair length is determined by the gene for fibroblast growth factor 5, with inactive copies of this gene causing long hair.^[44]

The Cat Genome Project, sponsored by the Laboratory of Genomic Diversity at the U.S. National Cancer Institute Frederick Cancer Research and Development Center in Frederick, Maryland, aims to help the development of the cat as an animal model for human hereditary and infectious diseases, as well as contributing to the understanding of the evolution of mammals.^[38] This effort led to the publication in 2007 of an initial draft of the genome of an Abyssinian cat called Cinnamon.^[35] The existence of a draft genome has led to the discovery of several cat disease genes,^[35] and even allowed the development of cat genetic fingerprinting for use in forensics.^[45]

Anatomy[link]

Diagram of the general anatomy of a male

Domestic cats are similar in size to the other members of the genus Felis, typically weighing between 4 kilograms (8 lb 13 oz) and 5 kilograms (11 lb 0 oz).^[22] However, some breeds, such as the Maine Coon, can exceed 11 kilograms (25 lb). Conversely, very small cats (less than 1.8 kilograms (3 lb 15 oz)) have been reported.^[46] The world record for the largest cat is 21.297 kilograms (46 lb 15.2 oz).^[47] The smallest adult cat ever officially recorded weighed around 1.36 kilograms (3 lb).^[48] Cats average about 23–25 centimeters (9–10 in) in height and 46 centimeters (18.1 in) in head/body length (males being larger than females), with tails averaging 30 centimeters (11.8 in) in length.^[49]

Cats have 7 cervical vertebrae like almost all mammals, 13 thoracic vertebrae (humans have 12), 7 lumbar vertebrae (humans have 5), 3 sacral vertebrae like most mammals (humans have 5 because of their bipedal posture), and a variable number of caudal vertebrae in the tail (humans retain 3 to 5 caudal vertebrae, fused into an internal coccyx).^[50]:11 The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and the pelvis.^{[50] :16} Unlike human arms, cat forelimbs are attached to the shoulder by free-floating clavicle bones, which allow them to pass their body through any space into which they can fit their heads.^[51]

Skull

The cat skull is unusual among mammals in having very large eye sockets and a powerful and specialized jaw.^[52]:35 Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two long canine teeth, inserting them between two of the prey's vertebrae and severing its spinal cord, causing irreversible paralysis and death.^[53] Compared to other felines, domestic cats have narrowly spaced canine teeth; which is an adaptation to their preferred prey of small rodents, which have small vertebrae.^[53] The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' small molars cannot chew food effectively.^[52]:37

Cats, like dogs, are digitigrades. They walk directly on their toes, with the bones of their feet making up the lower part of the visible leg.^[54] Cats are capable of walking very precisely, because like all felines they directly register; that is, they place each hind paw (almost) directly in the print of the corresponding forepaw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain. Unlike most mammals, when cats walk, they use a "pacing" gait; that is, they move the two legs on one side of the body before the legs on the other side. This trait is shared with camels and giraffes. As a walk speeds up into a trot, a cat's gait will change to be a "diagonal" gait, similar to other mammals: the diagonally opposite hind and forelegs will move simultaneously.^[55]

Like almost all members of the Felidae family, cats have protractable claws.^[56] In their normal, relaxed position the claws are sheathed with the skin and fur around the toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hind feet.^[57] Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, "kneading", or for extra traction on soft surfaces. Most cats have five claws on their front paws, and four on their rear paws.^[58] The fifth front claw (the dewclaw) is proximal to the other claws. More proximally, there is a protrusion which appears to be a sixth "finger". This special feature of the front paws, on the inside of the wrists, is the carpal pad, also found on the paws of big cats and dogs. It has no function in normal walking, but is thought to be an anti-skidding device used while jumping. Some breeds of cats are prone to polydactylyism, and may have eight or even ten toes.^[58] These are particularly common along the North-East coast of North America.^[59]

Physiology[link]

As cats are familiar and easily kept animals, their physiology has been particularly well studied; it generally resembles that of other carnivorous mammals but displays several unusual features probably attributable to cats' descent from desert-dwelling species.^[27] For instance, cats are able to tolerate quite high temperatures: humans generally start to feel uncomfortable when their skin temperature passes about 44.5 °C (112 °F), but cats show no discomfort until their skin reaches around 52 °C (126 °F),^[52]:46 and can tolerate temperatures of up to 56 °C (133 °F) if they have access to water.^[61]

Cats conserve heat by reducing the flow of blood to their skin and lose heat by evaporation through their mouth. They do not sweat, and pant only at very high temperatures.^[62] Unusually, a cat's body temperature does not vary throughout the day; this is part of cats' general lack of circadian rhythms and may reflect their tendency to be active both during the day and at night.^[63]:1 Cats' feces are usually dry and their urine is also highly concentrated, both of which are adaptations that allow cats to retain as much fluid as possible.^[27] Their kidneys are so efficient that cats can survive on a diet consisting only of meat, with no additional water,^[64] and can even rehydrate by drinking seawater.^[63]:29[65]

Cats are obligate carnivores: their physiology has evolved to efficiently process meat, and they have difficulty digesting plant matter.^[27] In contrast to omnivores such as rats, which only require about 4% protein in their diet, about 20% of a cat's diet must be protein.^[27] Cats are unusually dependent on a constant supply of the amino acid arginine, and a diet lacking arginine causes marked weight loss and can be rapidly fatal.^[66] Another unusual feature is that the cat also cannot produce the amino acid taurine, with taurine deficiency causing macular degeneration, where the cat's retina slowly degenerates, causing irreversible blindness.^[27] Since cats tend to eat all of their prey, they obtain minerals by digesting animal bones, and a diet composed only of meat may cause calcium deficiency.^[27]

A cat's digestive tract is also adapted to meat eating, being much shorter than that of omnivores and having low levels of several of the digestive enzymes that are needed to digest carbohydrates.^[67] These traits severely limit the cat's ability to digest and use plant-derived nutrients, as well as certain fatty acids.^[67] Despite the cat's meat-oriented physiology, several vegetarian or vegan cat foods have been marketed that are supplemented with chemically synthesized taurine and other nutrients, in attempts to produce a complete diet. However, some of these products still fail to provide all the nutrients that cats require,^[68] and diets containing no animal products pose the risk of causing severe nutritional deficiencies.^[69]

Senses[link]

Cats have excellent night vision and can see at only one-sixth the light level required for human vision.^[52]:43 This is partly the result of cat eyes having a tapetum lucidum, which reflects any light that passes through the retina back into the eye, thereby increasing the eye's sensitivity to dim light.^[70] Another adaptation to dim light is the large pupils of cats' eyes. Unlike some big cats, such as tigers, domestic cats have slit pupils.^[71] These slit pupils can focus bright light without chromatic aberration, and are needed since the domestic cat's pupils are much larger, relative to their eyes, than the pupils of the big cats.^[71] Indeed, at low light levels a cat's pupils will expand to cover most of the exposed surface of its eyes.^[72] However, domestic cats have rather poor color vision and (like most non-primate mammals) have only two types of cones, optimized for sensitivity to blue and yellowish green; they have limited ability to distinguish between red and green,^[73] although they can achieve this in some conditions.^[74]

Cats' whiskers are highly sensitive to touch.

Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hz up to 79 kHz, a range of 10.5 octaves; while humans can only hear from 31 Hz up to 18 kHz, and dogs hear from 67 Hz to 44 kHz, which are both ranges of about 9 octaves.^[75][76] Cats do not use this ability to hear ultrasound for communication but it is probably important in hunting,^[77] since many species of rodents make ultrasonic calls.^[78] Cat hearing is also extremely sensitive and is among the best of any mammal,^[75] being most acute in the range of 500 Hz to 32 kHz.^[79] This sensitivity is further enhanced by the cat's large movable outer ears (their pinnae), which both amplify sounds and help a cat sense the direction from which a noise is coming.^[77]

Cats have an acute sense of smell, which is due in part to their well-developed olfactory bulb and also to a large surface of olfactory mucosa, in cats this mucosa is about 5.8 cm² in area, which is about twice that of humans and only 1.7-fold less than the average dog.^[80] Cats are very sensitive to pheromones such as 3-mercapto-3-methylbutan-1-ol,^[81] which they use to communicate through urine spraying and marking with scent glands.^[82] Cats also respond strongly to plants that contain nepetalactone, especially catnip, as they can detect that substance at less than one part per billion.^[83] This response is also produced by other plants, such as Silver Vine and valerian, and may be caused by the smell of these plants mimicking a pheromone and stimulating cats' social or sexual behaviors.^[84]

Cats have relatively few taste buds compared to humans. Owing to a mutation in an early cat ancestor, one of two genes necessary to taste sweetness may have been lost by the cat family.^[39] Their taste buds instead respond to amino acids, bitter tastes and acids.^[85] To aid with navigation and sensation, cats have dozens of movable vibrissae (whiskers) over their body, especially their face. These provide information on the width of gaps and on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protective blink reflexes to protect the eyes from damage.^[52]:47

Health[link]

The average life expectancy for male indoor cats at birth is around 12 to 14 years,^[86] with females usually living a year or two longer.^[87] However, there have been reports of cats reaching into their 30s,^[88] with the oldest known cat, Creme Puff, dying at a verified age of 38.^[89] Feline life expectancy has increased significantly in recent decades.^[90] Having a cat neutered or spayed confers some health benefits, since castrated males cannot develop testicular cancer, spayed females cannot develop uterine or ovarian cancer, and both have a reduced risk of mammary cancer.^[91] The lifespan of feral cats is hard to determine accurately, although one study reported a median age of 4.7 years, with a range between 0 to 8.3 years.^[92]

Diseases[link]

Cats can suffer from a wide range of health problems, including infectious diseases, parasites, injuries and chronic disease. Vaccinations are available for many of these diseases, and domestic cats are regularly given treatments to eliminate parasites such as worms and fleas.

Poisoning[link]

In addition to obvious dangers such as rodenticides, insecticides and weed killers, cats may be poisoned by many chemicals that are usually considered safe.^[93] This is because their livers are less effective at some forms of detoxification than those of other animals, including humans and dogs.^[27][94] Some of the most common causes of poisoning in cats are antifreeze and rodent baits.^[95] It has also been suggested that cats may be particularly sensitive to environmental pollutants.^[93][96] When a cat has a sudden or prolonged serious illness without any obvious cause, it is possible that it has been exposed to a toxin.^{[citation needed]}

Human medicines should never be given to cats. For example, the painkiller paracetamol (also called acetaminophen, sold as Tylenol and Panadol) is extremely toxic to cats: even very small doses need immediate treatment and can be fatal.^[97][98] Even aspirin, which is sometimes used to treat arthritis in cats, is much more toxic to them than to humans and must be administered cautiously.^[93] Similarly, application of minoxidil (Rogaine) to the skin of cats, either accidentally or by well-meaning owners attempting to counter loss of fur, has sometimes been fatal.^[99] Essential oils can be toxic to cats and there have been reported cases of serious illnesses caused by tea tree oil, and tea tree oil-based flea treatments and shampoos.^[100]

Other common household substances that should be used with caution around cats include mothballs and other naphthalene products.^[93] Phenol-based products (Pine-Sol, Dettol (Lysol) or hexachlorophene)^[93] are often used for cleaning and disinfecting near cats' feeding areas or litter boxes but these can sometimes be fatal.^[101] Ethylene glycol, often used as an automotive antifreeze, is particularly appealing to cats, and as little as a teaspoonful can be fatal.^[102] Some human foods are toxic to cats; for example theobromine in chocolate can cause theobromine poisoning, although few cats will eat chocolate.^[103] Large amounts of onions or garlic are also poisonous to cats.^[93] Many houseplants are also dangerous,^[104] such as Philodendron species and the leaves of the Easter Lily, which can cause permanent and life-threatening kidney damage.^[105]

Behavior[link]

Free-ranging cats are active both day and night, although they tend to be slightly more active at night.^[106][107] The timing of cats' activity is quite flexible and varied, which means that house cats may be more active in the morning and evening (crepuscular behavior), as a response to greater human activity at these times.^[108] House cats have territories that vary considerably in size, in one study ranging from seven to 28 hectares (69 acres).^[107] Although they spend the majority of their time in the vicinity of their home, they can range many hundreds of meters from this central point.^[107] Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually 12–16 hours, with 13–14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term cat nap refers to the cat's ability to fall asleep (lightly) for a brief period and has entered the English lexicon—someone who nods off for a few minutes is said to be "taking a cat nap". During sleep cats experience short periods of rapid eye movement sleep accompanied by muscle twitches, which suggests that they are dreaming.^[109]

Sociability[link]

Social grooming in a pair

Although wildcats are solitary, the social behavior of domestic cats is much more variable and ranges from widely dispersed individuals to feral cat colonies that form around a food source, based on groups of co-operating females.^[110][111] Within such groups one cat is usually dominant over the others.^[112] Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, which are about ten times larger than those of female cats and may overlap with several females' territories.^[82] These territories are marked by urine spraying, by rubbing objects at head height with secretions from facial glands and by defecation.^[82] Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually chase away stranger cats, at first by staring, hissing, and growling, and if that does not work, by short but noisy and violent attacks. Despite some cats cohabiting in colonies, cats do not have a social survival strategy, or a pack mentality and always hunt alone.^[113]

Domestic cats use many vocalizations for communication, including purring, trilling, hissing, growling, snarling and several different forms of meowing.^[10] In contrast, feral cats are generally silent.^[114]:208 Their types of body language, including position of ears and tail, relaxation of whole body, and kneading of paws, are all indicators of mood. The tail and ears are particularly important social signal in cats, with a raised tail acting as a friendly greeting.^[115][116] Tail raising also indicates the cat's position in the group's social hierarchy, with dominant individuals raising their tails less often than subordinate animals.^[116] Nose-touching is also a common greeting and may be followed by social grooming, which is solicited by one of the cats raising and tilting its head.^[111] However, some pet cats are poorly socialized. In particular older cats may show aggressiveness towards newly arrived kittens, which may include biting and scratching; this type of behavior is known as Feline Asocial Aggression.^[117]

For cats, life in proximity with humans (and other animals kept by humans) amounts to a "symbiotic social adaptation". They may express great affection towards their human companions, especially if they imprint on them at a very young age and are treated with consistent affection. It has been suggested that, ethologically, the human keeper of a cat functions as a sort of surrogate for the cat's mother, and that adult domestic cats live their lives in a kind of extended kittenhood, a form of behavioral neoteny.^[118] Conversely, the high-pitched purrs cats make to solicit food may mimic the cries of a hungry human infant, making them particularly hard for humans to ignore.^[119]

Grooming[link]

The hooked papillae on a cat's tongue act like a hairbrush to help clean and detangle fur.

Cats intimidate opponents by arching their backs, raising their fur, turning sideways, and hissing.

Cats are known for their cleanliness, spending many hours licking their coats.^[120] The cat's tongue has backwards-facing spines about 500 micrometers long, which are called papillae. These are quite rigid, as they contain keratin.^[121] These spines allow cats to groom themselves by licking their fur, with the rows of papillae acting like a hairbrush. Some cats, particularly longhaired cats, occasionally regurgitate hairballs of fur that have collected in their stomachs from grooming. These clumps of fur are usually sausage-shaped and about two to three centimeters long. Hairballs can be prevented with remedies that ease elimination of the hair through the gut, as well as regular grooming of the coat with a comb or stiff brush.^[120] Some cats can develop a compulsive behavior known as psychogenic alopecia, or excessive grooming.^[122]

Fighting[link]

With domestic cats, males are more likely to fight than females.^[123] With feral cats, the most common reason for cat fighting is competition between two males to mate with a female: here most fights will be won by the heavier male.^[124] Another possible reason for fighting in domestic cats is the difficulty of establishing territories within a small home.^[123] Female cats will also fight over territory or to defend their kittens. Spaying females and neutering males will decrease or eliminate this behavior in many cases, suggesting that the behavior is linked to sex hormones.

When fighting, cats make themselves appear more impressive and threatening by raising their fur and arching their backs, thus increasing their apparent size.^[115] Often, the ears are pointed down and back to avoid damage to the inner ear and potentially listen for any changes behind them while focused forward. Attacks usually comprise powerful slaps to the face and body with the forepaws as well as bites, but serious damage is rare; usually the loser runs away with little more than a few scratches to the face, and sometimes the ears. Cats will also throw themselves to the ground in a defensive posture to rake their opponent's belly with their powerful hind legs.^[125]

Normally, serious injuries from fighting will be limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission of feline immunodeficiency virus (FIV).^[126] Sexually active males will usually be involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to the ears and nose.

Hunting and feeding[link]

Cats feed on small prey, primarily birds and rodents.^[127] Feral cats and house cats that are free-fed tend to consume many small meals in a single day, although the frequency and size of meals varies between individuals.^[113] Cats use two hunting strategies, either stalking prey actively, or waiting in ambush until an animal comes close enough to be captured. Although it is not certain, the type of strategy used may depend on the prey species in the area, with for example, cats waiting in ambush outside burrows, but tending to actively stalk birds.^[128]:153

Most breeds of cat have a noted fondness for settling in high places, or perching. In the wild, a higher place may serve as a concealed site from which to hunt; domestic cats may strike prey by pouncing from such a perch as a tree branch, as does a leopard.^[129] Other possible explanations include that height gives the cat a better observation point, allowing it to survey its territory. During a fall from a high place, a cat can reflexively twist its body and right itself using its acute sense of balance and flexibility.^[130] This is known as the cat's "righting reflex". It always rights itself in the same way, provided it has the time to do so, during a fall. The height required for this to occur is around 90 cm (3 feet). Cats without a tail also have this ability, since a cat mostly moves its hind legs and relies on conservation of angular momentum to set up for landing, and the tail is in fact little used for this feat.^[131] This leads to the proverb "a cat always lands on its feet".

Eating a house sparrow.

One poorly understood element of cat hunting behavior is the presentation of prey to human owners. Ethologist Paul Leyhausen proposed that cats adopt humans into their social group, and share excess kill with others in the group according to the local pecking order, in which humans are placed at or near the top.^[132] Anthropologist and animal scientist Desmond Morris, in his 1986 book Catwatching, suggests that when cats bring home mice or birds, they are teaching their human to hunt, or helping their human as if feeding "an elderly cat, or an inept kitten".^[133] Morris's theory is inconsistent with the fact that male cats also bring home prey, despite males having no involvement with raising kittens.^[128]:153

Domestic cats select food based on its temperature, smell and texture, strongly disliking chilled foods and responding most strongly to moist foods rich in amino acids, which are similar to meat.^[69][113] Cats may reject novel flavors (a response termed neophobia) and learn quickly to avoid foods that have tasted unpleasant in the past.^[113] They may also avoid sugary foods and milk; since they are lactose intolerant, these sugars are not easily digested and may cause soft stools or diarrhea.^[113][134] They can also develop odd eating habits. Some cats like to eat or chew on other things, most commonly wool, but also plastic, paper, string, aluminum foil/Christmas tree tinsel, or even coal. This condition is called pica and can threaten their health, depending on the amount and toxicity of the items eaten.^[135][136]